A coal roadway outburst prevention method for a barrier coal seam support

Abstract

The present invention provides a coal laneway anti-burst method for blocking a coal seam support body, in the technical field of comprehensive development and utilization of coal mine gas, comprising: performing gas concentration detection on the coal seam to obtain the gas concentration in different areas of the coal seam, performing mechanical analysis on the coal seam to obtain the relative geostress of the coal seam; dividing the gas grade of the coal seam according to the gas concentration in different areas of the coal seam, dividing the stress grade of the coal seam according to the relative geostress in different areas of the coal seam, and obtaining the stress gas grade area of ​​the coal seam after coupling; delineating a protection range according to the inclination of the coal seam, and implementing conventional strip anti-burst measures; within the strip protection area, cement mortar is injected into the coal body through a bottom pumping lane for reinforcement, and anchor rods are driven into the coal seam according to the stress gas grade area of ​​the coal seam to support the coal seam; the present invention divides the danger level area, reinforces the strip coal body on the basis of strip anti-burst, protects the area where deformation may occur, and thus ensures the rational utilization of coal mine gas.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive development and utilization of coal mine gas, and particularly relates to a coal roadway outburst prevention method for blocking coal seam support bodies. Background Art

[0002] Coal roadway outburst prevention refers to a series of preventive measures taken during the coal mine mining process against the possible coal and gas outburst phenomenon in the coal seam. Coal and gas outburst refers to a dynamic phenomenon during the coal mine mining process, in which the coal body suddenly ruptures under the combined action of ground stress and gas pressure, accompanied by a large amount of gas release. This outburst phenomenon has great destructiveness and danger.

[0003] Coal and gas outburst is affected by three factors: ground stress, gas, and the mechanical properties of the coal body. The existing coal roadway outburst prevention mainly focuses on the gas drainage in the coal seam, pays less attention to the roles of ground stress and the mechanical properties of the coal body, and lacks a technical method for blocking coal seam support bodies with different measures in different danger zones to solve the problem of soft coal failure under high stress conditions. As a result, low gas content / pressure accidents have occurred many times in recent years under the conditions of high stress and low-strength coal bodies, causing a large number of casualties. Especially with the continuous increase of the coal mine mining depth, such accidents will become more and more common. It is very necessary to control the coal body failure under different stress conditions. Summary of the Invention

[0004] To solve the above problems, the present invention provides a coal roadway outburst prevention method for blocking coal seam support bodies. By dividing the danger level areas, on the basis of strip outburst elimination, the strip coal body is reinforced to protect the areas that may deform, thereby avoiding the occurrence of outbursts. Specifically, it includes:

[0005] A coal roadway outburst prevention method for blocking coal seam support bodies, including:

[0006] Before the coal seam tunneling, detect the gas concentration of the coal seam to obtain the gas concentration in different areas of the coal seam, and conduct a mechanical analysis of the coal seam to obtain the relative ground stress of the coal seam;

[0007] Divide the gas grade of the coal seam according to the gas concentration in different areas of the coal seam, divide the stress grade of the coal seam according to the relative ground stress in different areas of the coal seam, and obtain the stress-gas grade area of the coal seam after coupling;

[0008] According to the coal seam dip angle, delimit the protection range and implement the conventional strip outburst elimination measures;

[0009] Within the strip protection area, inject cement mortar into the coal body through the bottom drainage roadway for reinforcement, and, according to the stress-gas grade area of the coal seam, drive bolts into the coal seam through the bottom drainage roadway to support the coal seam;

[0010] Start gas drainage operation;

[0011] Before the coal mining operation starts, remove the installed anchor bolts.

[0012] Optionally, the detection of the gas concentration in the coal seam to obtain the gas concentrations in different areas of the coal seam includes:

[0013] Before the coal seam tunneling, conduct structure detection on the working face through borehole detection technology, and combine with gas parameter testing to evaluate the gas concentrations in different areas of the coal seam, so as to obtain the gas concentrations in different areas of the coal seam.

[0014] Optionally, the division of the stress levels of the coal seam according to the relative ground stress in different areas of the coal seam includes:

[0015] Within a range of 50 m in the selected target area, use a stress gauge to determine the relative ground stress of the coal seam.

[0016] Optionally, the division of the gas grades of the coal seam according to the gas concentrations in different areas of the coal seam includes:

[0017] When Q min ≤Q < (Q min + Q max ) / 2, then the current area is a low gas area;

[0018] When Q ≥ (Q min + Q max ) / 2, then the current area is a high gas area;

[0019] Among them, Q min is the gas concentration in the area with the lowest gas concentration, Q is the gas concentration in the current area, and Q max is the gas concentration in the area with the highest gas concentration.

[0020] Optionally, the division of the stress levels of the coal seam according to the relative ground stress in different areas of the coal seam includes:

[0021] When σ min ≤σ < (σ min + σ max ) / 2, then the current area is a low stress area;

[0022] When σ ≥ (σ min + σ max ) / 2, then the current area is a high stress area;

[0023] Among them, σ min is the stress in the area with the lowest stress, σ is the stress in the current area, and σ max is the stress in the area with the highest stress.

[0024] Optionally, the stress-gas grade regions of the coal seam after coupling include:

[0025] Low stress and low gas region, high stress and low gas region, low stress and high gas region, and high stress and high gas region.

[0026] Optionally, the method of demarcating the protection range according to the dip angle of the coal seam and implementing the conventional strip outburst elimination measures includes:

[0027] When the dip angle of the coal seam ∈ [0°, 15°], the protection range is 20 m;

[0028] When the dip angle of the coal seam is greater than 15°, the protection range is 30 m;

[0029] According to the working face design, a plurality of boreholes are arranged along the roadway and evenly distributed at the edge of the strip protection area to implement the conventional strip outburst elimination measures.

[0030] Optionally, within the strip protection area, cement mortar is injected into the coal body through the bottom drainage roadway for reinforcement, and according to the stress-gas grade regions of the coal seam, anchor bolts are driven into the coal seam through the bottom drainage roadway to support the coal seam, including:

[0031] Before the grouting operation, boreholes are arranged in the bottom drainage roadway, and then cement mortar is injected into the coal body for reinforcement;

[0032] The grouting pressure should be controlled within the range of 1 / 2 - 2 / 3 of the in-situ stress of the current area;

[0033] Among them, the grouting pressure rises gradually;

[0034] Determine the length of the anchor bolts in each stress-gas grade region according to the coal seam thickness;

[0035] Determine the distance between the anchor bolts according to the stress-gas grade regions.

[0036] Optionally, the method of determining the length of the anchor bolts in each stress-gas grade region according to the coal seam thickness includes:

[0037] The length of the anchor bolts in the low stress and low gas region and the low stress and high gas region is 1.5 times the coal seam thickness;

[0038] The length of the anchor bolts in the high stress and low gas region and the high stress and high gas region is 2.5 times the coal seam thickness;

[0039] The method of determining the distance between the anchor bolts according to the stress-gas grade regions includes:

[0040] A plurality of rows of anchor bolts are evenly arrayed within each region. Within a single region:

[0041] When the area is a low-stress and low-gas area, the distance between two adjacent bolts in any horizontal row or any vertical column within this area is 10 m;

[0042] When the area is a low-stress and high-gas area, the distance between two adjacent bolts in any horizontal row or any vertical column within this area is 7 m;

[0043] When the area is a high-stress and low-gas area, the distance between two adjacent bolts in any horizontal row or any vertical column within this area is 4 m;

[0044] When the area is a high-stress and high-gas area, the distance between two adjacent bolts in any horizontal row or any vertical column within this area is 1 m.

[0045] The present invention protects the areas that may deform by strengthening the strip coal body in areas with different danger levels, thereby avoiding outbursts. Compared with the prior art, the above technical solution has at least the following beneficial effects: (1) It changes the traditional idea of outburst prevention technology in coal roadways that focuses on gas drainage, proposes the strip coal body strengthening technology, effectively enhances the stability of the coal seam support, protects the areas that may deform in advance, reduces the risk of coal and gas outbursts, and provides a new idea for coal and gas outburst prevention technology. (2) By comprehensively considering the control effects of the three elements of in-situ stress, gas, and coal body mechanical properties on outbursts, the outburst danger levels are carefully divided, and different-intensity control measures are implemented on this basis, which can achieve precise control of coal body failure under different stress and gas pressure conditions and improve the outburst prevention effect. (3) As the mining depth of coal mines increases, coal and gas outburst accidents under high-stress and low-strength coal body conditions will become more and more frequent. This technology has stronger pertinence compared with traditional gas control technologies. (4) By controlling the way of strip coal body failure to prevent and control coal and gas outburst disasters, the workload is lower than that of traditional gas drainage technology, which can reduce the outburst prevention cost and thus ensure the reasonable utilization of coal mine gas. Description of the Drawings

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0047] Figure 1 It is the bolt layout diagram of the present invention. Detailed Embodiment

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0049] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains. The "first", "second", and similar terms used in the present invention do not denote any order, quantity, or importance, but are only used to distinguish different components. Similarly, terms such as "a", "an", or "the" do not denote a quantity limitation, but indicate the presence of at least one. The terms "comprising" or "including" and the like mean that the elements or items appearing before the term cover the elements or items listed after the term and their equivalents, without excluding other elements or items. The terms "connected" or "coupled" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0050] It should be noted that the "upper", "lower", "left", "right", "front", and "rear" and the like used in the present invention are only used to represent relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0051] To solve the problems existing in the prior art, this embodiment provides a coal roadway outburst prevention method for a barrier coal seam support body. The main implementation contents include: before coal seam tunneling, conducting structure detection and gas parameter testing on the working face to determine the gas distribution; conducting mechanical analysis on the working face to determine the stress distribution; dividing the gas concentration from the lowest value Q min to the highest value Q max , dividing it into 2 grade regions. Similarly, dividing the stress from the lowest value σ min to the highest value σ maxDivide into two levels. By superimposing gas pressure and stress distribution, four level areas are formed: high stress and high gas area, low stress and high gas area, high stress and low gas area, and low stress and low gas area. According to the coal seam dip angle, delimit the protection range and implement conventional strip outburst prevention measures. Within the strip protection range, inject cement mortar into the coal body through the bottom gas drainage roadway for reinforcement. Drive bolts into the coal seam from the bottom gas drainage roadway to further support the coal seam. After the support and grouting are completed, start the gas drainage operation. After the outburst prevention measures for the roadway are completed, implement the outburst prevention measures for the working face, and before the coal mining operation starts, remove the installed bolts to further carry out the coal mining work of the coal seam. By dividing the dangerous level areas and strengthening the strip coal body on the basis of strip outburst prevention, the present invention protects the areas that may deform, thus avoiding the occurrence of outbursts.

[0052] The specific implementation method is as follows:

[0053] A coal roadway outburst prevention method for blocking coal seam support bodies includes:

[0054] S1. Before coal seam tunneling, detect the gas concentration of the coal seam to obtain the gas concentration in different areas of the coal seam, and conduct a mechanical analysis of the coal seam to obtain the relative in-situ stress of the coal seam:

[0055] Before coal seam tunneling, detect the structure of the working face through borehole detection technology, and combine with gas parameter testing to evaluate the gas concentration in different areas of the coal seam to obtain the gas concentration in different areas of the coal seam.

[0056] Within a range of 50 m in the selected target area, use a stress gauge to determine the relative in-situ stress of the coal seam.

[0057] In this step, detect the structure of the working face through borehole detection technology, combine with gas parameter testing to evaluate the gas concentration in the coal seam, and through these detection data, identify the gas content for subsequent determination of high gas and low gas areas;

[0058] Use numerical simulation methods to study the influence of factors such as mining layout, ground height, and coal seam structure on the stress field, and combine the data measured by stress gauges and numerical simulation to determine the high stress area and low stress area of the working face for subsequent use.

[0059] S2. Divide the gas grade of the coal seam according to the gas concentration in different areas of the coal seam, divide the stress grade of the coal seam according to the relative in-situ stress in different areas of the coal seam, and obtain the stress-gas grade area of the coal seam after coupling;

[0060] Among them, the division of the gas grade of the coal seam according to the gas concentration in different areas of the coal seam includes:

[0061] When Q min ≤Q < (Qmin + Q max When Q ≥ (Q

[0062] When Q ≥ (Q min + Q max ), the current area is a high gas area;

[0063] Among them, Q min is the gas concentration in the area with the lowest gas concentration, Q is the gas concentration in the current area, and Q max is the gas concentration in the area with the highest gas concentration.

[0064] Among them, the division of the stress level of the coal seam according to the relative ground stress in different areas of the coal seam includes:

[0065] When σ min ≤ σ < (σ min + σ max ), the current area is a low stress area;

[0066] When σ ≥ (σ min + σ max ), the current area is a high stress area;

[0067] Among them, σ min is the stress in the area with the lowest stress, σ is the stress in the current area, and σ max is the stress in the area with the highest stress.

[0068] Among them, the stress-gas grade areas of the coal seam after coupling include: low stress - low gas area, high stress - low gas area, low stress - high gas area, and high stress - high gas area.

[0069] In this step, mainly the gas concentration is divided from the lowest value Q min to the highest value Q max , dividing into 2 grade areas. Similarly, the stress is divided from the lowest value σ min to the highest value σ max dividing into 2 grades. By superimposing the gas pressure and stress distribution, four grade areas are formed, including:

[0070] According to the measured gas pressure, dividing it from the lowest value Q min to the average value (Q min + Q max ), average value (Q min +Q max ) to the highest value Q max , dividing into 2 grade areas: high gas area, low gas area;

[0071] Similarly, according to the measured stress, dividing it from the lowest value σmin to the average value (σ min + σ max ), the average value (σ min +σ max ) / 2 to the maximum value σ max , divide into two grade regions: high stress region, low stress region;

[0072] Superimpose the gas pressure and the stress distribution to form four grade regions: high stress and high gas region, low stress and high gas region, high stress and low gas region, low stress and low gas region.

[0073] S3. According to the coal seam dip angle, delimit the protection range and implement the conventional strip outburst elimination measures:

[0074] When the coal seam dip angle ∈ [0°, 15°], the protection range is 20 m;

[0075] When the coal seam dip angle is greater than 15°, the protection range is 30 m;

[0076] According to the working face design, arrange multiple boreholes along the roadway, evenly distributed at the edge of the strip protection area, and implement the conventional strip outburst elimination measures.

[0077] In this step, when the coal seam dip angle is small (0° - 15°), the strip widths on both sides are small, and the protection range is 10 - 20 m, take the protection range of 20 m; when the coal seam dip angle increases (15° - 30° or more), the strip widths on both sides need to be increased, and the protection range is 20 - 30 m, take the protection range of 30 m;

[0078] According to the working face design, arrange multiple boreholes along the roadway, evenly distributed at the edge of the strip protection area, and implement the conventional strip outburst elimination measures.

[0079] The conventional strip outburst elimination measures are existing technologies, such as gas drainage, borehole pressure relief, hydraulic punching, etc.

[0080] S4. Within the strip protection area, inject cement mortar into the coal body through the bottom drainage roadway for reinforcement, and, according to the stress - gas grade region of the coal seam, drive bolts into the coal seam through the bottom drainage roadway to support the coal seam;

[0081] Before the grouting operation, arrange boreholes in the bottom drainage roadway, and then inject cement mortar into the coal body for reinforcement; the grouting pressure should be controlled within the range of 1 / 2 - 2 / 3 of the in - situ stress in the current area, and the grouting pressure rises gradually.

[0082] During this operation, the grouting pressure should be controlled within the range of 1 / 2 - 2 / 3 of the in - situ stress in the current area. When starting the grouting, the grouting pressure needs to rise gradually (still controlled within the range of 1 / 2 - 2 / 3 of the in - situ stress) to ensure effective reinforcement of the coal seam.

[0083] As Figure 1 shown, determine the bolt length of each stress-gas grade area according to the coal seam thickness:

[0084] The bolt length in the low-stress and low-gas area and the low-stress and high-gas area is 1.5 times the coal seam thickness;

[0085] The bolt length in the high-stress and low-gas area and the high-stress and high-gas area is 2.5 times the coal seam thickness;

[0086] That is: determine the bolt length according to the coal seam thickness (H). Generally, the bolt length is 1.5 times the coal seam thickness, and in the high-stress area, the bolt length is 2.5 times the coal seam thickness;

[0087] As Figure 1 shown, determine the distance between each bolt according to the stress-gas grade area:

[0088] Multiple rows of bolts are evenly arranged in each area. In a single area:

[0089] When the area is the low-stress and low-gas area, the distance between two adjacent bolts in any horizontal row or any vertical column in this area is 10 m;

[0090] When the area is the low-stress and high-gas area, the distance between two adjacent bolts in any horizontal row or any vertical column in this area is 7 m;

[0091] When the area is the high-stress and low-gas area, the distance between two adjacent bolts in any horizontal row or any vertical column in this area is 4 m;

[0092] When the area is the high-stress and high-gas area, the distance between two adjacent bolts in any horizontal row or any vertical column in this area is 1 m.

[0093] This operation is specifically: determine the bolt length and spacing according to the above four divided areas. Among them, the bolt length in the high-stress and high-gas area is 2.5H, the spacing is 1 m, the bolt length in the high-stress and low-gas area is 2.5H, the spacing is 4 m, the bolt length in the low-stress and high-gas area is 1.5H, the spacing is 7 m, and the bolt length in the low-stress and low-gas area is 1.5H, the spacing is 10 m; according to the determined parameters, drive bolts into the coal seam in the bottom gas drainage roadway.

[0094] S5. Start the gas drainage operation:

[0095] After completing the support and grouting, start the gas drainage operation, reasonably arrange the gas drainage system, and gradually reduce the gas pressure in the coal seam;

[0096] S6. Before the mining operation starts, remove the installed bolts:

[0097] After the gas outburst prevention and control measures in the roadway are completed, implement the outburst prevention measures for the working face, and before the coal mining operation starts, remove the installed anchor bolts to further carry out the coal mining work of the coal seam, including:

[0098] After the gas outburst prevention and control measures in the roadway are completed, evaluate the effect of the gas outburst prevention and control measures in the roadway to ensure that the gas concentration meets the standard, and then implement the outburst prevention measures for the working face;

[0099] Before the coal mining operation starts, remove the installed anchor bolts to further carry out the coal mining work of the coal seam.

[0100] The present invention changes the traditional idea of coal roadway outburst prevention technology that focuses on gas drainage. By strengthening the rib coal body, the area that may deform is protected in advance, effectively enhancing the stability of the coal seam support body, reducing the risk of coal and gas outburst, thus avoiding the occurrence of outburst, and providing a new idea for the prevention and control technology of coal and gas outburst. Since the present invention comprehensively considers the control effects of the three elements of in-situ stress, gas, and coal body mechanical properties on outburst, it can achieve precise control of the coal body failure under different stress and gas pressure conditions, improving the outburst prevention effect. Under the condition of deep coal mining, compared with the traditional gas control technology, this technology has stronger pertinence for the problem of coal roadway outburst prevention and can reduce the construction workload and outburst prevention cost, thus ensuring the reasonable utilization of coal mine gas.

[0101] The following points need to be explained:

[0102] (1) The attached drawings of the embodiments of the present invention only relate to the structures involved in the embodiments of the present invention, and other structures can refer to the general design.

[0103] (2) For clarity, in the attached drawings used to describe the embodiments of the present invention, the thickness of the layer or region is enlarged or reduced, that is, these drawings are not drawn according to the actual scale. It can be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, the element can be "directly" on or under the other element or there can be an intermediate element.

[0104] (3) Without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0105] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for preventing coal roadway outbursts by blocking a coal seam support, characterized in that: include: Before coal seam excavation, gas concentration detection is performed on the coal seam to obtain the gas concentration in different areas of the coal seam, and mechanical analysis is performed on the coal seam to obtain the relative ground stress of the coal seam; Dividing the gas grade of the coal seam according to the gas concentration in different areas of the coal seam, and dividing the stress grade of the coal seam according to the relative ground stress in different areas of the coal seam, to obtain the stress gas grade area of ​​the coal seam after coupling; According to the inclination of the coal seam, the protection range is delineated and conventional strip outburst elimination measures are implemented; In the strip protection zone, cement mortar is injected into the coal body through the bottom pumping tunnel for reinforcement, and anchor bolts are driven into the coal seam through the bottom pumping tunnel according to the stress gas grade area of ​​the coal seam to support the coal seam; Start gas extraction operations; Before mining operations begin, the installed anchor bolts are removed.

2. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 1, characterized in that: The gas concentration detection of the coal seam to obtain the gas concentration of different areas of the coal seam includes: Before coal seam excavation, structural detection of the working face is carried out through drilling detection technology, and combined with gas parameter testing, the gas concentration in different areas of the coal seam is evaluated to obtain the gas concentration in different areas of the coal seam.

3. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 2, characterized in that: Classifying the stress levels of the coal seam according to the relative ground stresses in different areas of the coal seam includes: The relative ground stress of the coal seam is determined using a stress gauge within 50 m of the selected target area.

4. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 3, characterized in that: The gas grade of the coal seam according to the gas concentration in different areas of the coal seam includes: When Q min ≤Q<(Q min + Q max ) / 2, the current area is a low-gas area; When Q ≥ (Q min + Q max ) / 2, the current area is a high-gas area; Among them, Q min is the gas concentration of the area with the lowest gas concentration, Q is the gas concentration of the current area, and Q max The gas concentration is the area with the highest gas concentration.

5. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 4, characterized in that: The classification of the stress levels of the coal seam according to the relative ground stresses in different areas of the coal seam includes: When σ min ≤σ<(σ min + σ max ) / 2, the current area is a low stress area; When σ≥(σ min + σ max ) / 2, the current area is a high stress area; Among them, σ min is the stress of the area with the lowest stress, σ is the stress of the current area, and σ max is the stress in the area with the highest stress.

6. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 5, characterized in that: The stress gas grade area of ​​the coal seam after the coupling includes: Low stress and low gas area, high stress and low gas area, low stress and high gas area and high stress and high gas area.

7. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 6, characterized in that: According to the coal seam inclination, the protection range is delineated and conventional strip outburst elimination measures are implemented, including: When the coal seam inclination ∈ [0°, 15°], the protection zone is 20 m; When the coal seam inclination is greater than 15°, the protection zone is 30 m; According to the working face design, multiple drill holes are arranged along the tunnel, evenly distributed at the edge of the strip protection zone, and conventional strip outburst elimination measures are implemented.

8. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 7, characterized in that: In the strip protection zone, cement mortar is injected into the coal body through the bottom pumping tunnel for reinforcement, and anchor bolts are driven into the coal seam through the bottom pumping tunnel to support the coal seam according to the stress gas grade area of ​​the coal seam, including: Before the grouting operation, drill holes are arranged in the bottom extraction tunnel, and then cement mortar is injected into the coal body for reinforcement; The grouting pressure should be controlled within the range of 1 / 2-2 / 3 of the ground stress in the current area; Among them, the grouting pressure gradually increases; Determine the anchor length for each stress gas grade area according to the coal seam thickness; The distance between each anchor rod is determined according to the stress gas grade area.

9. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 8, characterized in that: Determining the anchor rod length in each stress gas grade area according to the coal seam thickness includes: The bolt length in low-stress low-gas areas and low-stress high-gas areas is 1.5 times the thickness of the coal seam; The bolt length in high stress low gas area and high stress high gas area is 2.5 times the coal seam thickness; Determining the distance between the anchor rods according to the stress gas grade area includes: Multiple rows of anchors are evenly arranged in each area, in a single area: When the area is a low-stress and low-gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 10m; When the area is a low stress and high gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 7m; When the area is a high stress and low gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 4m; When the area is a high-stress and high-gas area, the distance between two adjacent anchor rods in any horizontal row or any vertical column in this area is 1m.

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